Research oriented non-repudiation protocols have been active since the beginning of this millennium. It is time to take a step forward and realize that in many applications there are more than two entities. This book supports this statement. The volume provides state-of-the-art in non-repudiation protocols and gives insight of its applicability to e-commerce applications. This professional book organizes the existing scant literature regarding non-repudiation protocols with multiple entities participation. It provides the reader with sufficient grounds to understand the non-repudiation property and its applicability to real applications. This book is essential for professional audiences with in-depth knowledge of information security and a basic knowledge of applied cryptography. The book is also suitable as an advanced-level text or reference book for students in computer science.